Making concrete articles and the like



. comma OR, PLASTIC.

I 1' Patented at 5.1932

UNITED STATES" PATENT --oFF1ca GLENN n. WAGNER, or BELLEVILLE, ILLINOIS, ASSIGNOR TO ALUMINUM COMPANY or AMERICA, or rrrrsnonen, PENNSYLVANIA, A CORPORATION or PENNSYL vANIA A MAKING CONCRETE ARTICLES AND THE LIKE No Drawing. Application filed December 23, 1930. Serial No. 504,272.

This invention relates to the treatment of to this mixture in an amount corresponding hydraulic cement-aggregate mixtures with to about 11 per cent by weight of the amount bauxite residue for the purpose of developing of Portland cement added, will produce a in such mixtures uniformity of physical comfinal concrete product which, after settin for 5. position and strength. A further object of three days, will have a tensile strength 300 the invention isthe provision of a hydraulic pounds per square inch, whereas the same cement-aggregate mixture of high strength. Portland cement-sand mixture without the Bauxite residue. sometimes, known as red addition of the bauxite residue will have a mu ,ls c 11150 n eres1 ue remalnmg rom tensile strength after three days of only 195 the treatment of aluminous ore, such as. pounds per square inch. If to this same mixbauxite, with alkali-dissolving agents which ture is added bauxite residue in an amount remove from the ore a major portion of its corresponding to about per cent of the alumina content. The-bauxite residue is comweight of the Portland cement used therein,

cxa

osed hiefl ofthe oxides of aluminum iron 1 s1 icon 1 amum 'jca c1u'm.-an so mm; s 1t min the form of a powder of minute particle size. The particlesrthereof are porous and capable of a sorbing water. I have discovered that the addition of an amount of bauxite residue to hydraulic cement-aggregate mixtures increases the physical uniformity of such mixtures and produces a product of uniform strength. I have also discovered that hydraulic cement-aggregate mixtures to which bauxite residues have been added in accordance with my invention have, after setting, higher strengths than are usually developed in such mixtures under similar conditions.

The amount of residue which should be added in order to achieve the results of my invention will vary somewhat with the particular type of cement and aggregate used,

as well as with the particular proportions in which the cement and aggregate are mixed. In usual cases, I have found that an amount of bauxite residue corresponding from about 5 to 20 per cent by Weight of the amount of cement used in the mixture will produce satisfactory results, and in the case of Portland.

cement and sand mixtures, I prefer to use an amount of residue corresponding to about 10 per cent by weight of the amount of Portlandcement in the mixture.

In practicing my invention in connection with a cement-aggregate mixture composed of 20 per cent of Portland cement per cent of sand and 10 per cen o wa er covered that the addition have disof Bauxite residue M the concrete after three days will have a tensile strength of approximately 382 pounds per square inch. Moreover, the concrete mixtures to which bauxite residue was added in the amounts above named have a more uniform distribution of the aggregate within the mixture than did the concrete sample to which no bauxite residue was added. While increased strength is an important factor, a uniformity of the aggregate throughout the mass of the hydraulic cement-aggregate mixture is of considerably greater importance since the segregation of aggregate in the ocment-aggregate mixture will and does result in planes of weakness in the concrete struc-' ture.

The addition of bauxite residue to the cement-aggregate mixtures may be accomplished in any convenient way. For instance, the bauxite residue may be mixed with the cement at the time it is packed in containers for shipment. Likewise, the proper quantity of bauxite residue may be introduced into the mixing machine during the well known mixing processes by which the cement and the aggregate are mixed with water to form the usual concrete slurry which is then cast to form the desired article.

The novel eflI'ects produced in the practice of my invention by the addition of small amounts of bauxite residue to hydraulic cement-aggregate mixtures are probably explained in part on the theory that the finely divided residue disseminates uniformly throughout the mixture and, by virtue of its physical and chemical reaction with the water, forms a gel-like substance which, acting mo as a matrix throughout the mixture of the hydraulic cement and aggregate particles, tends to promote a smooth and uniform movement therebetween, thus creating the highly desired uniform mixing of the materials. It is my theo also that the particles of the bauxite resi ue, by virtue of their propensity to adsorb water, act as carriers for a part of the water of the mixture and tend to distribute it uniformly throughout the mixture and in contact with the hydraulic cement particles, thus insuring uniform hydration or setting. The practice of my invention is, however, readily accomplished without reference to the above explanation and I do not desire to be limited to any theory herein set forth as to the methods in which the novel effects of my invention are produced.

Having thus described my invention, 1 claim:

1. The method of developing uniformity in hydraulic cement-aggregate mixtures comprising adding to the mixture, bauxite residue from the treatment of bauxite with an alkaline solvent.

2. The method of developing uniformity in hydraulic cement-aggregate mixtures comprising adding to the mixture bauxite residue from the treatment of bauxite with an alkaline solvent, and mixing it thoroughly therewith.

- 3. The method of developing uniformity in hydraulic cement-aggregate mixtures comsignature.

prisin mixing therewith a bauxite residue from t e treatment of bauxite with an alkaline solvent, characterized by fine particle size and adsorbent qualities.

4. A composition of matter comprising cement capable of setting by hydration, and bauxite residue from the treatment of bauxite with an alkaline solvent.

5. A composition of matter comprising cement capable of setting by hydration and bauxite residue from the treatment of bauxite with an alkaline solvent, in intimate admixture.

6. An article of hydrated cement and an aggregate, having disseminated therethrough, bauxite residue from the treatment of bauxite with an alkaline solvent.

7. A cast article of hydrated cement and an aggregate, having bauxite residue from the treatment of bauxite with an alkaline solvent, in the form of minute particles distributed through the article with substantial uniformity.

In testimony whereof I hereto afiix my GLENN H. WAGNER. 

